Effects of Storm Attenuation Over Satellite Links in Sub-Tropical Africa

One of the key requirements of 5G wireless network technologies is the 99.999% system availability. In order to achieve this objective, wireless network links need to be designed appropriately. The implementation of 5G technology and its eventual integration with communication satellites will deliver the much needed high speeds (up to 4 GB/s) and correspondingly much lower latency (down to 1 ms). To enable the achievement of such high speed communication, wireless links need to operate at the higher frequency regions in the Ku-band and above. Unfortunately, at these high frequencies, the wavelength of the propagating signal is comparable in size to the raindrops, so as to be easily absorbed and scattered by the larger rain drops present in the falling rain. Recent rain drop size distribution measurement campaigns across the continent have shown that there is an increase in the concentration of larger drops in a unit volume as the rainfall rate increases. This increase in the size of the rain drop is the main source of signal attenuation along a microwave path. On this premise, this paper investigates the effect of rain storms, and more precisely, extreme rain storm events, on a satellite-earth links operating at frequencies in the Ku-band and above. The investigation is carried out through rain drop size distribution (DSD) modelling on rainfall storm events over Durban, South Africa (29° 52'S, 30° 58'E). Using the Mie Scattering theory and rain drop size distribution models, rain statistics at R0.01 and R0.001 are used to determine rain attenuation thresholds for microwave links design.